It also looks like the red conductor in the wire either pulled out of its screw terminal inside the plug housing or snapped when someone yanked or tripped on it.

Hey, at least they're using a plug!

I saw a similar hi-amp "cordset" that was connected to a portable generator's socket. The conductor ends were thrust into the socket holes and held in place with wooden shish-kebob skewers. This was at a street fair with lots of food vendors.